1. Field of the Invention
The present invention relates to a multilayer ceramic capacitor and a mounting board thereof.
2. Description of the Related Art
Since a multilayer ceramic capacitor (MLCC), a multilayer chip electronic component, has advantages such as a small size, high capacitance and easiness of mounting, the multilayer ceramic capacitor may be used in various electronic devices.
For example, the multilayer ceramic capacitor may be used as a chip shaped condenser mounted on circuit boards of various electronic products such as a display device, for example, a liquid crystal display (LCD), a plasma display panel (PDP), and the like, a computer, a personal digital assistants (PDA), and a mobile phone to serve to charge electricity or discharge electricity.
Generally, the multilayer ceramic capacitor may have a structure in which a plurality of dielectric layers and internal electrodes having different polarities between the dielectric layers are alternately disposed.
In this case, since the dielectric layer has piezoelectricity, when direct current (DC) or alternate current (AC) voltage is applied to the multilayer ceramic capacitor, a piezoelectric phenomenon is generated between the internal electrodes, thereby generating periodic vibrations while expanding and contracting a volume of a ceramic body according to the frequency.
Such vibrations are transferred to a circuit board through an external electrode of the multilayer ceramic capacitor and a solder connecting the external electrode to the circuit board, such that the entire circuit board may become an acoustically reflective surface to generate vibration sound, noise.
In this case, the solder connecting the external electrode and the circuit board is inclined from both side surfaces and both end surfaces of the ceramic body along a surface of the external electrode at a predetermined height. As a volume and a height of the solder increase, vibrations of the multilayer ceramic capacitor may be further easily transferred to the circuit board, such that vibration sound may be further severe.
Such a vibration sound may have a frequency corresponding to an audible frequency in a region of 20 to 20,000 Hz causing a user discomfort. The vibration sound causing the user discomfort as described above is called acoustic noise.
Recently, in electronic devices, since acoustic noise generated in the multilayer ceramic capacitor as described above due to the tendency for low noise components may rather increase, research into technology for effectively reducing the acoustic noise generated in the multilayer ceramic capacitor has been required.
Although a multilayer ceramic capacitor is disclosed in the following Related Art document, contents limiting a ratio of a width of an external electrode to a length of margin part of a ceramic body in a length direction are not disclosed therein.